Be kind to the guy - he is obviously not a pilot and English may not be his first language. I would guess his question is really referring to autorotation (disabled rotors = disengaged rotors = autorotating ??? - he did not say "Rotors stopped")
I don't have a figure for Bell 222 but would guess at around 2 500 feet per minute in a stabilised auto ??? Sure someone will give you a more accurate figure
